Electronics > Repair

HP 6654A Opt.J23

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kjk24:
Hi,

the Powersupply HP 6654A has Option J23 Label on the backside.
Has someone more information for the Option J23 ?, i found this but its only a sellers information
6654A-J23
Output voltage: 0 to 60 V (0-80V opt.J23)
Output current (40°C): 0 to 9 A (0-6A opt.J23)

I repair it for a while now.
The voltage is higher then expected and current is to low.
I cant calibrate it with the standard eeprom setting becouse the calibration constants dose not fit to the values what the device produce during calibration.

i changed the calibration eeprom settings to fit with the Voltage what the PS generate (~75V).
like this i can calibrate the Voltage and overvoltage. But the current is strange, when i start the calibration the first current point is around 0.4A and the second point it shows UNR and the current is only 5.6A with a 0.11Ohm Resistor.

i made the calibration Basic Programms to python and use a Agilent GPIB interface to reprogramm the eeprom Settings, i attatch it. (you should know what you do with the scripts !! have a look into it first !)

has some one A unit and can readout the eeprom constants for me please ? i can assist how to doit.

thanks a lot.
greetings KK

Jay_Diddy_B:
Hi KK,

I went through a similar process with another Agilent power supply. Take a look at this thread:

https://www.eevblog.com/forum/testgear/hp-6673a-power-supply-removing-option-j08/msg4607125/#msg4607125

Look at the pdf file attached to that message. You will probably have to similar changes to the control board.
I have a standard 6654A here. I could extract the EEPROM contents.

Regards,
Jay_Diddy_B

Jay_Diddy_B:
kjk24

I have read the EEPROM contents from a working HP6654A for you. I have formatted the data in the same format that is presented in the HP Service Manual:


--- Code: ---
Read from a working HP6654A

ReadOnly Eprom_data_6654 = New Decimal() {
64.8304, 16.4637, 61.425, 0, 83, 0, 390.422, 137.804, 9.214, 0,
99, 1, 10.5739, 75.75, 66, 0, 83, 255, 20, 10,
6654, 60.819, 168.195, 403.354, 168.119, 1767, 6, 255, 0, 0,
16, 6654, 0, 20, 180, 20, 180, 156, 37, 26,
186, 15, 20, 0, 4}

The initalization values from the HP Service Manual

 ReadOnly Eprom_data_6x54 = New Decimal() {
        64, 16.35, 61.425, 0, 83, 0, 393, 127, 9.214, 0,
        99, 1, 10.43, 78.2, 66, 0, 83, 255, 20, 10,
        6654, 60.81, 168, 405.41, 168.18, 1768, 5, 255, 0, 0,
        16, 6554, 0, 20, 180, 20, 180, 156, 37, 26,
        186, 15, 20, 0, 4}

--- End code ---


I believe that you will need to change some resistors on the control board to remove the option. On the units that I remove the option, there was flux residue on the resistors that had been changed by HP.

I hope that this helps.

Regards,
Jay_Diddy_B

kjk24:
Thank you verry much for the data, i will compare it withmy settings . I have the eeprom layout documented , it is not finished but i will post it maybe you have information too for it. The resin info dose not help anymore 👍 because i replaced a lot of components in the unit. I can now cal the voltage and overvolt to 80volt the current cal still fail the second cc cal is unr and the current is 5.4amp. i post more later.




eeprom Data mean
hex/dec
0x02 2=  ?  the knob step fine/corse is changed but the Displayed value is changed too , 5=0.2, 1000=0.001, 500=0.002, 200=0.005, 100=0.01 , its overwritten during CV calibration, 48.5658
0x06 6= ? 15.8446

0x0A 10= Volt Max 82.0000
0x1C 28= Current Max 6.0
0x20 32= 0

0x14 20= ?  the knob step fine/corse is changed but the Displayed value is changed too , 5=0.2, 1000=0.001, 500=0.002, 200=0.005, 100=0.01 , its overwritten during CC calibration
0x18 24= DAC out in CC Mode ?

0x26 38= OVCal constants 1
0x2A 42= OVCal constants 2
0x2E 46= Overvolt Max 82.5000
0x32 50= 0
0x40 64= Password 6654
0xA5 165= HPIB ADDRESS 5
0x9E 185= Model Number 6654
0x44 68= LCD CV constants 1
0x48 72= LCD CV constants 2

0x4c 76= LCD CC constants 1
0x50 80= LCD CC constants 2

higher constants lower LCD Voltage are shown,
the allowed setting for the VCal const2 wars -/+ ~10V

the eeprom attatched picture are the constants (Little-Endian) marked with Sizes from the Service Manual

best Regards,
kk

Jay_Diddy_B:
kjk24,


I think this part of software in the Service Manual gives the locations of the calibration data:


--- Code: ---2380 Fact_cal_sour: ! Address of factory calibration data source
2390 DATA 2,6,68,72,20,24,76,80,150
2400 !
2410 Fact_cal_dest: ! Address of factory calibration data destination
2420 DATA 84,88,92,96,100,104,108,112,116
2430 !
2440 Fact_cal_len: ! Length of factory calibration data
2450 DATA 4,4,4,4,4,4,4,4,2
2460 !
2470 RESTORE Fact_cal_sour
2480 F0R I=1 TO 9
2490 READ Cal_sour_addr(I)
2500 NEXT I
2510 !
2520 RESTORE Fact_cal_dest
2530 FOR I=1 T0 9

--- End code ---


These locations are not changed by HP's program

84,88,92,96,100,104,108,112,116

The Source locations are:

2,6,68,72,20,24,76,80,150



ReadOnly Eprom_data_6654 = New Decimal() {
      64.8304, 16.4637, 61.425, 0, 83, 0, 390.422, 137.804, 9.214, 0,
      99, 1, 10.5739, 75.75, 66, 0, 83, 255, 20, 10,
      6654, 60.819, 168.195, 403.354, 168.119, 1767, 6, 255, 0, 0,
      16, 6654, 0, 20, 180, 20, 180, 156, 37, 26,
      186, 15, 20, 0, 4}


I have indicated the calibration data in red.


                64.8304, 16.4637, 61.425, 0, 83, 0, 390.422, 137.804, 9.214, 0,
      99, 1, 10.5739, 75.75, 66, 0, 83, 255, 20, 10,
      6654, 60.819, 168.195, 403.354, 168.119, 1767, 6, 255, 0, 0,
      16, 6654, 0, 20, 180, 20, 180, 156, 37, 26,
      186, 15, 20, 0, 4}

HPIB ADDRESS IS 6

Password 6654

Model Number 6654


Regards,
Jay_Diddy_B






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